In recent years, as next-generation energy, various types of fuel cell modules and fuel cell devices have been proposed to date. The fuel cell module is constructed by locating, in a housing, a cell stack device constructed by securing a cell stack, which is composed of a plurality of fuel cells capable of generating electric power by utilizing a hydrogen-containing gas (fuel gas) and air (oxygen-containing gas) that are juxtaposed so as to be electrically connected in series with each other, to a manifold for effecting gas supply to the fuel cells. The fuel cell device is constructed by locating the fuel cell module in an exterior case.
In the fuel cell module and fuel cell device of this type, generation of electric power can be accomplished by feeding a fuel gas to the fuel electrode layer side of the fuel cell and feeding an oxygen-containing gas (air, in general) to the air electrode layer side thereof.
In a fuel cell having an air electrode layer formed in the interior thereof, there is the possibility of backflow of a fuel gas flowing the outside of the fuel cell that will eventually lead to damage to the fuel cell (air electrode layer). In view of this, technologies for covering an air electrode layer with a dense member made of ceramics such as zirconia and alumina are proposed for the purpose of preventing damage to the air electrode layer (refer to Patent Literature 1, for example).
Moreover, in a fuel cell constituted so that an excess of fuel gas left unused after power generation is burned at one end of the fuel cell, there is proposed a fuel cell in which a porous conductive support substrate situated around a gas discharge port is impregnated with an inorganic component composed mainly of zirconia for the purpose of protecting the front end of the fuel cell from damage caused by heat of combustion (refer to Patent Literature 2, for example).